The present invention relates to a novel family of compositions based on alkyl polyglycosides and fatty alcohols, which are especially useful for the preparation of stable emulsions the whiteness of which is improved with respect to that obtained with compositions of the state of the art.
The invention especially finds application in the cosmetic field.
Alkyl glycosides or alkyl polyglycosides (APG's) are well-known non-ionic surfactant compounds which can be used alone or in combination with other surfactants in a wide range of industrial applications, and especially in the cosmetic field.
Alkyl polyglycosides have firstly been used as foaming agents, and in this application, those the alkyl chain of which comprises 8 to 14 carbon atoms have proved to be particularly interesting.
More recently, alkyl polyglycosides have been used as emulsifiers, and in this application, those the alkyl chain of which comprises 16 to 18 carbon atoms have proved to be particularly interesting.
The patent application WO 92/06778, in the name of the Applicant, describes, for the first time, the use of mixtures of alkyl polyglycosides and fatty alcohols as self-emulsifying agents.
The term &lt;&lt;self-emulsifying&gt;&gt; designates any agent or composition which is capable of forming a stable emulsion with an aqueous phase, practically without the provision of energy, for example by dispersion in the aqueous phase by slow mechanical agitation.
More specifically, the mixtures described in this prior art document comprise:
60 to 90% by weight of at least one fatty alcohol having 12 to 22 carbon atoms, and preferably 16 to 18 carbon atoms; and PA1 10 to 40% by weight of an alkyl polyglycoside, the alkyl part of which is preferably identical to that of the fatty alcohol. PA1 5 to 60% by weight of a mixture of alkyl polyglycosides constituted essentially of: PA1 70 to 5% by weight of a mixture of alkyl polyglycosides of formulae (III) and (IV): EQU R.sub.3 O(G.sub.3).sub.x3 (III) EQU R.sub.4 O(G.sub.4).sub.x4 (IV) PA1 95 to 40% by weight of one or more alcohols of formula R'OH, in which R' is a linear or branched aliphatic radical having 14 to 22 carbon atoms, and preferably of a mixture constituted of alcohols the alkyl part of which is identical to the alkyl part R.sub.1, R.sub.2, R.sub.3 and R.sub.4 of the above-mentioned alkyl polyglycosides. PA1 10 to 98% by weight of at least one alcohol having 16 to 18 carbon atoms; PA1 90 to 2% by weight of at least one alcohol having 20 to 22 carbon atoms. PA1 30 to 70% by weight of a mixture of alkyl polyglycosides of formulae (I) and (II) as defined above; and PA1 70 to 30% by weight of a mixture of alkyl polyglycosides of formulae (III) and (IV) as defined above. PA1 5 to 40% by weight, and preferably 10 to 20% by weight, of the above-mentioned mixture of alkyl polyglycosides; and PA1 95 to 60% by weight, and preferably 90 to 80% by weight, of one or more alcohols mentioned above. PA1 5 to 60% by weight, and preferably 10 to 20% by weight, of a mixture of alkyl polyglycosides constituted essentially of: PA1 95 to 40% by weight, and preferably 90 to 80% by weight, of a mixture constituted of alcohols the alkyl part of which is identical to the alkyl part R.sub.1, R.sub.2, R.sub.3 and R.sub.4 of the above-mentioned alkyl polyglycosides, or as defined above. PA1 oils of plant origin, such as sweet almond oil, coconut oil, castor oil, jojoba oil, olive oil, rapeseed oil, groundnut oil, sunflower oil, wheat germ oil, maize germ oil, soya oil, cotton oil, lucerne oil, poppy oil, marrow oil, evening primrose oil, millet oil, barley oil, rye oil, safflower oil, canelle nut tree oil, passionflower oil, hazelnut oil, palm oil, shea butter, apricot stone oil, Alexandria laurel tree oil, sysymbrium oil, avocado oil, calendula oil; PA1 modified plant oils such as the products known under INCI designations Apricot Kernel Oil PEG-6 esters and Olive Oil PEG-6 esters; PA1 oils of natural origin, such as perhydrosqualene, squalene; PA1 mineral oils, such as liquid paraffin, and mineral oils, notably originating from petroleum fractions, such as isoparaffins, having a boiling point between 300 and 400.degree. C.; PA1 synthetic oils, notably fatty acid esters such as butyl myristate, propyl myristate, cetyl myristate, isopropyl palmitate, butyl stearate, hexadecyl stearate, isopropyl stearate, octyl stearate, isocetyl stearate, dodecyl oleate, hexyl laurate, propylene glycol dicaprylate, ester derivatives of lanolic acid, such as isopropyl lanolate, isocetyl lanolate, triglycerides such as glycerol triheptanoate, alkylbenzoates, isoparaffins, polyalphaolefins, polyolefins, synthetic isoalkanes such as isohexadecane, isododecane, and silicone oils. Amongst the latter oils, dimethyl polysiloxanes, methylphenylpolysiloxanes, amine-modified silicones, fatty acid-modified silicones, alcohol-modified silicones, alcohol- and fatty acid-modified silicones, polyether group-modified silicones, epoxy-modified silicones, fluoro group-modified silicones, cyclic silicones, and alkyl group-modified silicones, may be more particularly cited.
The self-emulsifiable compositions described in the above-mentioned application are marketed under the designation Montanov.RTM. 68 and comprise a mixture of alkyl polyglycosides the fatty chains of which comprise 16 and 18 carbon atoms, as well as a mixture of fatty alcohols of the same fatty chain length.
If such compositions are perfectly satisfactory especially as regards the stability of the emulsions that they enable obtaining, it has been observed that these emulsions were not entirely satisfactory from the point of view of their whiteness, and this constitutes a non-negligible drawback for their applications in the cosmetic field.